Template:Infobox helium

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Helium, 2He
Template:Infobox element/symbol-to-top-image/alt
Helium
Pronunciation/ˈhliəm/ (HEE-lee-əm)
Appearancecolorless gas, exhibitin a reid-orange glow when placed in a heich-voltage electric field
Standard atomic weight Ar, std(He)4.002602(2)[1]
Helium in the periodic cairt
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gowd Mercur (element) Thallium Leid (element) Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium
-

He

Ne
hydrogenheliumlithium
Atomic nummer (Z)2
Groupgroup 18 (noble gases)
Periodperiod 1
Blocks-block
Element category  Noble gas
Electron confeeguration1s2
Electrons per shell2
Pheesical properties
Phase at STPgas
Meltin pynt(at 2.5 MPa) 0.95 K ​(−272.20 °C, ​−457.96 °F)
Bylin pynt4.22 K ​(−268.93 °C, ​−452.07 °F)
Density (at STP)0.1786 g/L
when liquid (at m.p.)0.145 g/cm3
whan liquid (at b.p.)0.125 g/cm3
Creetical pynt5.19 K, 0.227 MPa
Heat o fusion0.0138 kJ/mol
Heat o vapourisation0.0829 kJ/mol
Molar heat capacity5R/2 = 20.786 J/(mol·K)
Vapour pressur (defined bi ITS-90)
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K)     1.23 1.67 2.48 4.21
Atomic properties
Oxidation states0
ElectronegativityPauling scale: no data
Covalent radius28 pm
Van der Waals radius140 pm
Colour lines in a spectral range
Spectral lines o helium
Ither properties
Naitural occurrenceprimordial
Creestal structurhexagonal close-packed (hcp)
Hexagonal close-packed creestal structur for helium
Speed o soond972 m/s
Thermal conductivity0.1513 W/(m·K)
Magnetic orderindiamagnetic[2]
CAS Nummer7440-59-7
History
DiskiveryPierre Janssen, Norman Lockyer (1868)
First isolationWilliam Ramsay, Per Teodor Cleve, Abraham Langlet (1895)
Main isotopes o helium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct
3He 0.000137%* stable
4He 99.999863%* stable
  • Atmospheric value, abundance mey differ elsewhaur.
| references
style="text-align:left"|
in calc from C diff report ref
C −272.20
K 2.5 0.950 1.55 delta
F −457.96 −457.960 0
WD none 0.95 kelvin -272.05 Celsius -458 Fahrenheit Edit this at Wikidata
input C: −272.20, K: (at 2.5 MPa) 0.95, F: −457.96
comment
style="text-align:left"|
in calc from C diff report ref
C −268.93
K 4.22 4.22 0
F −452.07 −452.07 0
WD -268.9 Celsius Edit this at Wikidata
input C: −268.93, K: 4.22, F: −452.07
comment

References

Thir references will appear in the airticle, but this list appears anerly on this page.
  1. Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
  2. Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.